Automotive fuel



United States Patent Ofiice 3,034,875 Patented May 15, 1062 3,034,875AUTOMOTIVE FUEL John P. Buckmann, Yorba Linda, Calif, assignor to UnionOil (Iompany of California, Los Angeles, Calif, a corporation ofCalifornia No Drawing. Filed Aug. 6, 1956, Ser. No. 602,455 4 Claims.(Cl. 44-58) This invention relates to automotive fuels suitable for V(use in modern high compression automotive engines. More particularly itrelates to gasolines which produce a smaller octane requirement increase(R1) when used in automotive engines than ordinary gasolines.

It is well known that a clean engine, i.e. one from which depositswithin the combustion chambers have been removed, has a lower octanerequirement than does an engine which has been operated until the amountof deposits within the combustion chambers has reached equilibrium suchas is or may be obtained by operating the engine with a given fuel forthe equivalent of 3000 to 5000 or more road miles.

By the term octane requirement of an engine is meant the octane numberor rating of a fuel which just prevents knocking (audible knockuponacceleration) of the engine. By the term octane requirement increaseor 0R1 of an engine is meant the'difference in octane requirement of anengine containing combustion chamber deposits as compared with the sameengine from which combustion chamber deposits have been removed.Although the ORI refers to the increase in octane requirement of anengine the term will be applied to a fuel herein in the following sense.A gasoline or fuel which causes large ORI values in an engine will bereferred to as one having a high ORI. Conversely a fuel which causesonly small ORI values in an engine will be referred to as one having alow ORI. Furthermore additives described herein are said to reduce the0R1 characteristics of the fuel, meaning that the fuel containing theadditives will, on use in an engine, cause less octane requirementincrease in the engine than will the base fuel without such additives.

It is known that starting with a clean engine the octane requirement ofthe engine increases as combustion chamber deposits build up in theengine and continues to increase until an equilibrium amount of depositsare formed. Other factors influencing the octane requirement include thecondition of carburetor and ignition system including breaker points,spark plugs, etc.

With commercial automotive fuels, e.g., gasolines of various gradesavailable on the market it is found that the ORI of automotive engineswill generally be in the order of 6 to 9 or more octane numbers. Suchincreases in octane requirements are highly objectionable as is wellknown since the higher the octane requirement the higher the cost offuel necessary to operate the engine efilciently.

It is an object of this invention to provide an automotive gasolinecontaining additive materials which impart to the gasoline lowered ORIcharacteristics.

It is another object of this invention to provide a gasoline suitablefor use in modern high compression automotive internal combustionengines which gasoline does not increase the octane requirement of anengine to'an objectionable degree, and at least the use of which doesnot cause an ORI in the engine which is as great as that caused by theuse of fuels without such ORI additive.

A particular object of this invention is to provide a gasoline suitablefor use in present day high compression internal combustion automotiveengines which contains anti-knock agents such as tetraethyl lead(T.E.L.), antioxidants and/or gum inhibitors and to which is added smallamounts of an agent or agents which reduce the OR I characteristics ofthe gasoline.

It has been found that by adding very small amounts of lecithin with orwithout small amounts of a paraflinic type mineral lubricating oil toautomotive gasolines, engines operating on the resulting fuels show anORI substantially less than the corresponding ORI observed withgasolines which do not contain these additives.

The lecithin may be a purified lecithin but preferably is a commerciallecithin such as one obtained from soya bean oil and referred to as aplastic lecithin which contains approximately 65% of lecithin in soyaoil. Also available commercially is a liquid lecithin product containingabout 60% of lecithin in soya bean oil and this product may be employedas the lecithin portion of the additive combination. Under anycircumstance, the lecithin itself appears to be the active agent and thefatty oil with which it is associated in the various commercial productsdoes not appear to have deleterious effects, at least in the amounts inwhich it is present. Moreover, it is to be noted that the materialreferred to herein as lecithin comprises a mixture of acetone-insolublephospha- {tides and it is on the basis of acetone solubility that thepercentage of lecithin in the commercial products is determined.

The amount of lecithin to be employed to impart the desired low ORlcharacteristics to a gasoline will be less than 0.002% and preferablyless than 0.0015% by weight based on the gasoline. At the lowerconcentrations amounts as low as 0.0001% are found to be effective andpresumably amounts less than 0.000l% will be effective in reducing ORI.A particularly preferred range will be between 0.0002% and 0.001% byweight based on the finished fuel. I

These amounts are based upon commercial lecithin containingapproximately 65% lecithin corresponding amounts of pure lecithin, asdescribed above, would be less than about 0.00 l3% and preferably lessthan 0.00098% with amounts as low as about 0.000065% being effective.The particularly preferred range being between 0.000l3% and .00065% Inthe following discussion and in the claims unless otherwise noted theterm lecithin will be used to describe and will particularly refer tothe commercial 65% lecithin.

The above amounts of lecithin used alone or in combination withparaffinic mineral oil as described below are found to reduce ORIcharacteristics of gasolines to which they are added. The efiect is notlimited to one type of gasoline but is observed in substanitally anyhigh octane gasoline whether or not it contains anti-knock agents and/or gum inhibitors, or the like.

The second additive material which appears to cooperate with lecithin togive the desired lower ORI in fuels containing the additive is aparaffinic mineral lubricating oil of about medium grade. The oil may bean untreated distillate oil providing it is of relatively low waxcontent or it may be a dewaxed distillate oil. Preferably the oil is adewaxed, solvent-treated paraifinic type distillate oil of about mediumto light lubricating oil grade. The fol- TABLE I Characteristics ofHydrocarbon Oils Suitable for Use With Lecithin in Gasoline Over-allPreferred Ideal Range Range Gravity. A.P.I. at 60 F 34. -26. 0 32.0-26.528.6 Viscosity, SSU at 100 F 150-1, 00 250-500 318 Viscosity, SSU at 210F 2. 3-77. 45 75 52.2 Viscosity Index Above 60 above 80 85Viscosity-gravity Constant 0. 790-0. 825 0. 8000 820 0.817 Flash point,COG, F 410-500 425-475 445 Pour Point, F 20 20 5 Distillation, F.:

Initial 660-750 680-725 700 690 8l5 720-790 760 720 865 760-850 815 765'970 800 -930 892 95-99 98-99 99 a Values calculated to atmosphericpressure from vacuum distillation data. Distillation made at l to 5 mm.Hg pressure.

Methods of dewaxing and solvent treating lubricating oil fractions arewell known and need not be described herein except to point out that thedewaxing, which may be effected by substantially any method, with orwithout the aid of a dewaxing solvent, should produce a finished oilhaving a pour point not higher than about 20 F. Moreover, the solventtreatment may be carried out using any of the well known selectivesolvents which remove the more aromatic fractions leaving the moreparaffinic fractions. Suitable oils are obtained from Waxy or parafiinicWestern crude oils, from Mid-Continent type oils or from Eastern orPennsylvania type crude oils.

It is essential that the lubricating oil have a viscosity between about42 and 78 SSU at 210 F. and a flash point of at least about 400 F. sincelighter oils do not appear to have the characteristics required.

Just what effect the mineral oil has in combination with lecithin is notentirely understood although it is believed that possibly its primaryelfect is to prevent deposition of the lecithin in the induction systemof the engine. It is thus believed to be a carrier for the lecithin andinsures that all of the lecithin present in the fuel is carried into thecombustion chamber. It is possible also that the lubricating oil may insome way cooperate with the lecithin in reducing ORI.

When mineral oil is used, the amount will be less than about 0.01% andpreferably less than about 0.0075% based on the finished gasoline. Anyamounts less than these appear to have some effect and serve thepurposes described. Generally, when such oil is added it will be inamounts approximately equal to or greater than the amounts of lecithinup to 10 to times the amount of lecithin employed so long as the amountremains below the upper limit indicated. Generally between about 0.0001and 0.01% will be employed.

Gasolines or automotive fuels to which the lecithin or lecithin and oilmay be added to produce the lowered ORI effect include substantially allgrades of gasoline presently being employed in automotive and internaltained by thermal and/or catalytic cracking methods. In such case, thegasolines will contain gum inhibitors and may or may not contain T.E.L.Generally automotive and aircraft gasolines contain both straight-runand cracked stocks with or without alkylated hydrocarbons, reformedhydrocarbons and the like. The preparation of straight-run, alkylated,reformed and cracked stocks for blending in the preparation ofautomotive gasolines, aircraft gasolines, and the like, are well knownand need not be further described. Gasolines suitable for use in presentday automotive engines with which this invention is primarily concernedwill generally have the characteristics shown in Table II and it isprimarily to gasolines of the character indicated to which the additiveof this invention is added and found to be effective.

* Determined by ASIM method D-381. b AS'IM method D-86.

The above data were obtained on two commercial gasolines of the gradesindicated and are believed to be typical of commercial gasolinesmarketed at the present time. These gasolines contain 2-3 ml. oftetraethyl lead per gallon and 5 to 15 pounds of a phenolic type guminhibitor per 1000 gallons. It is to be pointed out that the usefulnessof the additive of this invention is not limited to gasolines of thetypes indicated as would be understood in the art. The same additive iseffective in gasolines of lower or higher volatility as well asgasolines having lower or higher knock rating, many of which gasolinesare presently commercially available. Gasolines which contain guminhibitors may contain single materials or combinations of suchinhibitors. The use of gum inhibitors is well known in the art and neednot be further described. It might be pointed out that the inhibitorsare generally aromatic compounds containing amino and/or hydroxyl groupsand it should be mentioned further that the particular gum inhibitor orinhibitors employed does not appear to have any appreciable efiect onthe ability of the described additive combination to perform thefunctions described herein.

Since both the lecithin and the hydrocarbon oil employed are readilysoluble on gasoline no difficulty is encountered in preparing theimproved fuels of this invention. Lecithin may be sepaartely added toand dissolved in the fuel or if oil and lecithin are to be added theymay first be combined, the lecithin being dissolved in the oil and theresulting solution added to the gasoline. Moreover, the separatematerials or the oil solution of lecithin may be dissolved in a smallportion of the gasoline or in a small amount of one of the stocks usedin preparing the finished gasoline and the resulting concentrate used inpreparing the finished gasoline. Preferably the additive or additiveswill be added and mixed into the gasoline during the blending operationsor at the time of incorporating lead and/ or gum inhibitor in thegasoline or gasoline stocks. It is to be noted that the lecithin atleast must not be added to the stocks or gasoline prior to a sweeteningtreatment in which caustic or the like is employed.

Tests to determine the ORI characteristics of gasolines with and withoutthe lecithin and lecithin and mineral oil additives of this inventionhave been run in standard 1952 and 1955 Oldsmobile S-cylinder enginesequipped with 4 barrel carburetors. In these tests a clean engine is runwith the fuel to be tested for a period of 160 hours using a cyclicoperation involving alternate periods of high and low speeds which willbe described more fully in connection with each engine. At the end ofthis period the carburetor is replaced with a test carburetor which ismaintained in perfect operating condition and by using reference fuelsof known octane rating the octane requirement of the dirty engine isdetermined. At this time the cylinder head is removed and all combustionchamber deposits are removed. The cylinder head is replaced, and usingthe test carburetor the octane requirement of the engine is againdetermined. The difference between the octane requirement of the dirtyengine and the clean engine is the ORI produced by the gasoline undertest. It is often referred to as the ORI of the gasoline.

In these tests the 1952 engine is operated for a total of 160 hours,equivalent to a road mileage of 6,400 miles. In this case the engine isoperated for 36 seconds at 2000 r.p.m., a load of 46 pounds and at abrake horsepower of 23 and then for 24 seconds at 1100 r.p.m. a load of15 pounds and at a brake horsepower of 4. This cycle is repeated duringthe entire run.

The 1955 engine is operated for 160 hours, equivalent to a road mileageof 7680 miles. In this case the engine is operated for 27 seconds at2000 rpm, a load of 46 pounds and a brake horsepower of 23 and then for33 seconds at 1100 r.p.m. with no load and a brake horsepower of 0. Thiscycle is repeated throughout the test. In the case of both engines andthroughout the tests, cooling water is controlled so as to maintain anoutlet temperature of 165 F .i-5 F. with an inlet temperature of F. toF. below the outlet temperature and oil temperatures are maintained at175 F15 F. An S.A.E. 1030 grade solvent treated paraflinic mineral oilfor A.P.I. services MS, MM, ML, and DG is used in the crankcase and ischanged after 60 and 120 hours of operation. Makeup oil is added each 8hours as required to maintain the correct oil level in the engine.

The results of tests on the following gasolines with and withoutlecithin and lecithin and oil are as follows:

c Diflerence between ORI of base tueland base fu el plus additives.

b A premium gasoline of 95 octane rating containing straight-run andcatalytically cracked hydrocarbon base stocks, 3 of lead per gallon and.005% by weight of a phenolic type gum inhibitor. This fuel hascharacteristgs silmilar to those shown in Table II in the column headedremium aso ines.

E; A dewaxed, solvent extracted Western parafiinlc mineral oil havingthe characteristics set forth in Table I, last column.

TABLE IV 0R1 Tests m 1952 Oldsmobile Engine Fuel Octane RequirementAdditive ORI Effect 1 No. Composition Dirty Clean 1 Basefuel 84.8 75.89.0 2 Fuel No. 1 Plus 0.0007% 82.6 77.7 4.9 4.1

lecithin. 3 Fuel N0. 1 Plus 0.001% 82.4 78.7 3.7 5.3

lecithin and 0.01% oil. 4 Fuel No. 1 Plus 0.0005% 81.1 77.0 4.1 4.9

lecithin and 0.005% oil. 5 Fuel No. 1 Plus 0.0013% 84.6 78.6 6.0 3.1

lecithin and 0.009% oil. 6 Base Fuel 83.0 75.0 8.0 7 Fuel No. 6 Plus0.0007% 81.5 76.9 4.6 3.3

, lecithin. 8 Fuel No. 6 Plus 001% 80.9 76.0 4.9 3.1

lecithin and 0.005% oil.

a Difference between ORI of base fuel and base fuel plus additives b Apremium gasoline of octane rating containing straight-run andcatalytically cracked hydrocarbon base stocks, 3 ml. of lead per gallonand 005% by weight of a phenolic type gum inhibitor. This fuel hascharacteristics similar to those shown in Table II in the column headedPremium Gasolines.

A dcwaxed,solvent extracted, western paratnnic mineral oil having thecharacteristics set forth in Table I, last column.

d A regular grade gasoline having an octane rating of 84 and containingcracked and straight-run base stocks, 2 ml. of lead per gallon and.0035% by weight of a phenolic type gum inhibitor. This gasoline hascharacteristics similar to those shown in Table II in the column headedBegular Gasolines."

Although the above-described engine tests were made with a gasolinecontaining tetraethyl lead and gum inhibitor, the advantageous ORIeffects of the lecithin and lecithin plus paraiiinic hydrocarbon oil areobserved as well in gasolines which do not contain tetraethyl leadand/or gum inhibitors. Engine tests on gasolines which dot not containlead and/or gum inhibitor substantiate this position. The amount of leadwhich may be employed in preparing gasolines to which the additives ofthis invention may be added may thus vary from 0 to as high as about 5ml. of tetraethyl lead per gallon. Generally, automotive gasolines willcontain 1 to 3 m1. of T.E.L. per gallon and aviation fuels may containas high as 4.5 or 5 ml. per gallon.

Gum inhibitors which may be employed in amounts generally ranging fromabout 5 pounds to about 25 pounds per 1000 barrels of gasoline includesubstantially any of the gum inhibitors which are now universallyemployed in the preparation of automotive and aviation gasolines. Theparticularly preferred gum inhibitors are aromatic ring compounds havingaliphatic and hydroxyl substituents. Ditertiarybutyl paracresol has beenfound to be very satisfactory. In view of the fact that gasolineinhibitors are well known in the art and are universally employed intodays gasolines, a further description of these materials is consideredto be unnecessary.

The above description and examples of our invention are illustrative ofthe broader aspects of this invention and are not to be taken aslimiting the invention as set forth in the following claims.

I claim:

-1. An internal combustion engine fuel consisting essentially ofhydrocarbons boiling in the gasoline boiling range containing less thanabout 0.002% by weight of lecithin but sufficient to impart reduced ORIcharacteristics to said fuel, and containing also less than about 0.01%by weight of a paraffinic hydrocarbon oil of medium lubricating oilgrade having a viscosity at 210 F. of between about 42 and about 78S.S.U., a flash point between 410 F. and 500 F., and a viscosity indexgreater than about 60, but sufficient to prevent deposition of saidlecithin in the induction system of an engine operating on said fuel.

2. An internal combustion engine fuel consisting essentially ofhydrocarbons boiling in the gasoline boiling range containing less thanabout 0.002% by weight of lecithin but sufiieient to impart reduced ORIcharacteristics to said fuel, and containing also between about 0.0001%and about 0.01% by weight of paraffinic hydrocarbon oil of mediumlubricating oil grade having a viscosity at 210 F. of between about 42and about 78 S.S.U., a flash point between 410 F. and 500 F., and aviscosity index greater than about 60, but sufiicient to preventdeposition of said lecithin in the induction systern of an engineoperating on said fuel.

3. An internal combustion engine fuel consisting essentially ofhydrocarbons boiling in the gaso ine boiling range and containing up toabout ml. of tetraethyl lead per gallon, between about 5 and 25 poundsper 1000 barrels of a gum inhibitor to which is added less than 0.002%by weight of lecithin but sufficient to impart reduced ORIcharacteristics to said fuel, and containing also less than about 0.01%by weight of a parafiinic hydrocarbon oil of medium lubricating oilgrade having a viscosity at 210 F. of between about 42 and about 78S.S.U., a flash point between 410 F. and 500 F., and a viscosity indexgreater than about 60, but suflicient to prevent deposition of saidlecithin in the induction system of an engine operating on said fuel.

4. An internal combustion engine fuel consisting essentially ofhydrocarbons boiling in the gasoline boiling 5 range and containing upto about 5 ml. of tetraethyl lead per gallon, between about 5 and poundsper 1000 barrels of a gun inhibitor to which is added less than 0.002%by weight of lecithin but sufiicient to impart reduced ORIcharacteristics to said fuel, and containing also between about 0.0001%and about 0.01% by weight of a paraffinic hydrocarbon oil of mediumlubricating 'oil grade having a viscosity at 210 F. of between about 42and about 78 S.S.U., a flash point between 410 F. and 500 F., and aviscosity index greater than about 60, but suflicient to preventdeposition of said lecithin in the induction system of an engineoperating on said fuel.

References Cited in the file of this patent UNITED STATES PATENTS2,155,678 Oosterhout Apr. 25, 1939 2,165,651 Rees et al July 11, 19392,207,430 Burk et al July 9, 1940 2,208,105 Rathbun July 16, 19402,322,007 Fischer June 15, 1943 2,352,760 Bell July 4, 1944 2,365,377Bell Dec. 19, 1944 2,405,560 Campbell Aug. 1 3, 1946 2,437,041 ProellMar. 2, 1948 FOREIGN PATENTS 464,055 Great Britain Apr. 12, 1937 733,820Great Britain July 20, 1955

1. AN INTERNAL COMBUSTION ENGINE FUEL CONSISTING ESSENTIALLY OFHYDROCARBON BOILING IN THE GASOLINE BOILING RANGE CONTAINING LESS THANABOUT 0.002% BY WEIGHT OF LECITHIN BUT SUFFICIENT TO IMPART REDUCED ORICHARACTERISTICS TO SAID FUEL, AND CONTAINING ALSO LESS THAN ABOUT 0.01%BY WEIGHT OF A PARAFFINIC HYDROCARBON OIL OF MEDIUM LUBRICATING OILGRADE HAVING A VICOSITY AT 210* F. OF BETWEEN ABOUT 42 AND ABOUT 78S.S.U., A FLASH POINT BETWEEN 410* F. AND 500* F., AND A VISCOSITY INDEXGREATER THAN ABOUT 60, BUT SUFFICIENT TO PREVENT DIPOSITION OF SAIDLECITHIN IN THE INDUCTION SYSTEM OF AN ENGINE OPERATING ON SAID FUEL.